Drug delivery devices allowing for multiple dosing of a required dosage of a liquid medicinal product, such as liquid drugs, and further providing administration of the liquid to a patient, are as such well-known in the art. Generally, such devices have substantially the same purpose as that of an ordinary syringe.
Pen-type injectors of this kind have to meet a number of user specific requirements. For instance in case of those with diabetes, many users will be physically infirm and may also have impaired vision. Therefore, these devices need to be robust in construction, yet easy to use, both in terms of the manipulation of the parts and understanding by a user of its operation. Further, the dose setting must be easy and unambiguous and where the device is to be disposable rather than reusable, the device should be inexpensive to manufacture and easy to dispose. In order to meet these requirements, the number of parts and steps required to assemble the device and an overall number of material types the device is made from have to be kept to a minimum.
Document EP 1 642 607 A1 for instance discloses a dose display mechanism consisting of a dose setting dial and a counter ring each displaying indices on their outer circumference arranged such that a two-indices representation of the selected dose can be displayed. The dose setting dial and the counter ring comprise single digits that are visible through a display window of a housing.
The digits are displayed in a readable orientation when the drug delivery device is oriented substantially horizontally. Since most drug delivery devices are designed for right-handed users, the digits are displayed in a correct and upright orientation when from a user's point of view, the distal end section of the device points to the left and when the proximal end section of the device points to the right hand side.
Such a display orientation is particularly applicable, where the user or patient holds the housing of the drug delivery device with his left hand while manipulating the device with his right hand, e.g. for setting and/or dispensing of a dose.
A left-handed user typically utilizes such pen-type injectors in a different way. Left-handed users typically hold the device with their right hand while making use of their left hand for dose setting and dose dispensing. With respect to the fixed display orientation of the dose setting dial, a left-handed user is thus compelled to turn over the device for reading the information illustrated in the display window. Hence, utilization of a standard drug delivery device turns out to be quite cumbersome for a left-handed user. As a consequence, left-handed might be exposed to reading errors or misinterpretation of the displayed information. Finally, the patient might be in danger of dispensing an incorrect dose.
A simple solution to this problem could be achieved by manufacturing of different drug delivery devices that are particularly designed for right- and left-handed users. However, production of drug delivery devices of different type and their configuration implies an increase in manufacturing complexity.